渗流和双向地震下跨海减震隧道的稳定分析

摘要

In order to study the structural stability of sea-crossing shock absorption tunnel subjected to the ac-tions of seepage and bidirectional earthquake,dynamic finite element static strength reduction method was used, and the structure field and fluid field models were established using ADINAsoftware in this paper,respective-ly.Considered factors included the effect of viscoelastic artificial boundary,seepage and bidirectional earth-quake,the influences of dynamic stability on the water depth,the thickness of overlying rock and the coefficient of permeability with shock absorption layer of cross sea tunnel as well as the transition law of plastic zone were studied.The results show that when subjected to the action of seepage and bi -directional earthquake,plastic zone of cross sea tunnel with shock absorption first appears at two arch feet and peripheral parts of arch shoulder, while it doesn’t appear at the arch top.The thicker the overlying rock is,the less improvement in seismic safety factor the shock absorption layer results in.The varying sea water depth and the coefficient of permeability have little effect on the safety factor when shock absorption layer is used.The overlying rock thickness makes greater influence on the safety coefficient of the tunnel when subjected to seepage and bidirectional earthquake than the water depth and the coefficient of permeability.%为了研究渗流和双向地震作用下跨海减震隧道工程结构的稳定性，采用动力有限元静力强度折减法，并利用ADI-NA软件分别建立了结构场和流体场分析模型。考虑黏弹性人工边界、双向地震和渗流的影响，研究海水深度、覆岩厚度和渗透系数对设置减震层跨海隧道动力稳定安全系数的影响以及塑性区的变化规律。研究结果表明：渗流和双向地震作用下，跨海减震隧道结构的塑性区最先出现在隧道结构的两侧拱脚和拱肩周边部位，拱顶部位没有出现塑形区；覆岩厚度越厚，设置减震层对跨海隧道在地震作用下的安全系数提高越少；海水深度和渗透系数的变化对设置减震层跨海隧道结构的安全系数影响不大；覆岩厚度的变化对跨海隧道在渗流和地震作用下安全系数的影响大于海水深度和渗透系数的影响。